Government mandate, environmental concerns and rising fuel costs have prompted engine companies to develop engines and ground transportation vehicles with improved mileage and reduced emissions. Improved engine concepts include use of higher compression ratio, low-temperature combustion systems, such as HCCI, PCCI and the like dual fuel concepts, fuel cell electric vehicles that utilize on-board reforming and a variety of hybrids including plug-in electric hybrids.
Many of these new engine types are likely to run on currently and widely available fuels. However it is likely that the optimal fuel is different in composition than the fuels available today. Some new engines, in-fact, may require the use of new fuel formulations.
New engines will, however, replace current conventional engines at a limited rate as new cars are introduced and old models removed from service. It is necessary to create a fueling station that has the flexibility to provide both new formulations as well as more conventional fuels. In addition, these same environmental and cost concerns have resulted in increased development and availability of fuels from renewable resources.
These fuels include ethanol and bio-diesel. Biodiesel generally refers to fatty acid methyl ester (FAME), where the fatty acid is derived from vegetable oils or animal fats. Because of the range of possible feedstocks, FAME biodiesels are not all the same but can have a range of physical properties. FAME biodiesel is generally used as a blend with petroleum-derived diesel. Engine manufacturers, however, do not necessarily warranty their engines over the entire range of biodiesel blends. Nor do all manufacturers set the same upper limit for biodiesel blends in their engine warranties. It is necessary to limit the amount of biodiesel blend in order to keep the engine in warranty. Furthermore, FAME biodiesels often have higher freezing points and viscosity than petroleum-derived diesel. For this reason the maximum amount of biodiesel blended with petroleum-derived diesel can also vary with the seasonal temperatures.
Ethanol in a similar fashion is generally used as a blend with petroleum-derived gasoline. The highest common level of blend, so called E85, is 85% ethanol. More commonly used concentration ranges of 3-10% are often set by mandate. Not all automobiles, however, are able to run over this entire concentration range. Again, it is necessary to limit the upper level of ethanol in the gasoline formulation.
At the same time, customers will have a range of preferences for their fuel characteristics. Customers have different sensitivities to cost, performance and the environmental impact. Some consumers will want to use the maximum percent of renewable fuel comment within warrantee, while others will prefer less.
It would be desirable to have a bio-fuels fueling system which assured that fuels used in the motor vehicle are within the manufacturer's specified range for warranty compliance. The instant invention provides such a solution.